ath10k: fix hw scan cancelling

If mac80211 decides to cancel a hw scan and FW is
not behaving properly (i.e.  doesn't want to abort
scan at all) we must call
ieee80211_scan_completed(). Otherwise no more
scans will be initiated, ever.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: sync WMI interface to FW 636

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>